doctype
html
    head
        meta
        title jade测试页面
        style.
            div{ width: 100px;height: 100px;background: #ccc;margin: 10px auto;text-align: center;}
    body
        -var i=0;
        while i<12
            if i%4==0&&i!=0
                div #{i++}
            else
                div #{i++}